Guillain-Barre Syndrome (GBS) also known as Acute Inflammatory Demyelinating Polyneuropathy (AIDP) is an acute polyneuropathy, which is a result of immune reaction to an infection. Rarely axons may also be affected in a rare variety of this type of neuropathy. Every year 2 out of 100000 are affected by this ailment.
1. Underlying Mechanism:
Guillain-Barre Syndrome (GBS) is an inflammatory condition and its hallmark is inflammation mediated demyelination of peripheral nerves. Demyelination can occur to nerve roots and distal to nerve root at any place along the course of the nerve.
This condition has been stated to occur as a result of autoreactive T cells and humoral antibodies, which are targeted against antigens of peripheral nerves. These T cells and antibodies specifically affect peripheral nerves and do not react with any other organ. T cells and antibodies are generated by preceding infections due to molecular mimicry.
There will be history of ascending paralysis along with sensory symptoms however sensory signs are rarely found. Patient will give history of preceding infection especially that of respiratory tract infection or gastroenteritis. Rarely paralysis can be in descending order affecting upper limbs first. Progression of paralysis remains for 4 weeks followed by plateau and then recovery.
There will be signs of lower motor neuron paralysis including areflexia, flaccid paralysis and diminished tone. Sensory impairment in glove and stocking distribution can also be found but is not very profound. Cranial nerves and autonomic system can also be involved resulting in fixed pupils. Autonomic involvement may lead to urinary retention, ileus, fluctuating blood pressure and irregular heart beat.
There are various variants of Guillain-Barre Syndrome including:
I. Miller Fisher Syndrome, which is characterized by ataxia, areflexia and ophthalmoplegia.
II. Polyneuritis Cranialis, which predominantly cranial nerves and is expressed as relevant signs and symptoms.
III. Pure sensory variant as Acute Sensory Axonal Neuropathy (ASAN).
IV. Pharyngeal-cervical-brachial variant, which affects head, neck and upper limbs.
V. Acute autonomic variant presenting as signs and symptoms of autonomic dycfunction.
VI. Axonal variant as acute Acute Motor and Sensory Axonal Neuropathy (AMSAN).
VII. Acute Motor Axonal Neuropathy (AMAN).